December C.E.T

[Jonnie G]

The next ten days should see a conservative CET figure of 2C it could easily be closer to 1C. By the 20th the CET should be close to the December average, and below average for the time of the month, possibly in the 4's.

[West is Best]

so with the PFJ way north

It has been south for a lot of the time. The key though is the amplification, which has been extensive since June. Not for 20 years or so can I recall the PFJ being so regularly south of the UK. It all began in June and was well south through July. Then, as you indicate, it has alternated and is now heading way south again - remarkably so. If ever there were a sign of a pattern change of major proportions this would be it. There's much to be said that the PFJ heading north in the mid to late 80's was responsible for the demise of UK winter PlC. Currently, without tempting fate, we might just be back in the old pattern once more. The jet chart at T144 is remarkable:

It does all make me wonder whether we've missed a trick or two about cycles in the long term, and overlooked the impact of El Nino in the short term. The La Nina set up may now be showing its hand strongly too.

Anyway, a major downward shift now. The overnight GFS and UKMO (particularly the former) retain a potent cold high then easterly in reliable timeframe with some penetrating night frosts. In the light of the last couple of months I'd like to see the CET kick well below the mean by 20th in case there's a milder reversion in the final third. Currently the CET by 20th looks to be little or no higher than 4.5C

Edited December 11, 2007 by La Nina

[Stu_London]

Down to 8.1C at the 10th (thanks to www.climate-uk.com)

The real falls start from today

I fully expect 2.5 to 3 degrees to be lost be the end of Sunday which should have us about average by then. If the high doesn't sink and/or we get a northerly for Xmas, we could finish the month over 1C below average which would be remarkable for a winter month in the christmas pudding.

I'd also like to hear from SF, as to whether he feels a sub 2C is no longer possible in the UK?

[Weather-history]

Could be a fall of 0.4 or even 0.5 after today.

[JohnAcc]

This is how I see Dec finishing up from here. I would estimate a 5.4 / 5.5 ish finish which will be slightly above the 10 year mean. It's very early doors yet and obviously subject to change depending on how long the block holds and whether we end up in a southerly flow after / (If) the high sinks.

Rgds, John

PS Does anyone know where I can find the running mean through the month for the 61-90 and 71-00 averages?

Edited December 11, 2007 by JohnAcc

[BLAST FROM THE PAST]

It does all make me wonder whether we've missed a trick or two about cycles in the long term, and overlooked the impact of El Nino in the short term. The La Nina set up may now be showing its hand strongly too.

Richard

As you know I'm a cycle supporter and we have entered perturbation cycle on Feb 2007 [La Nina domination from El Nino domination]...funny the El Nino 'collapsed' in Feb and folk were surprised...I wasn't as I followed Theodore Landscheidts predictions and were very good. I say were as he is dead now since 2003 but he predicted this and also sun cycle 23 being quieter than expected and 24 being much quieter and this seems a very good call.

Just to stay on topic the mild period over Christmas IMO will keep us at around mid 5s possibly 6./

BFTP

Edited December 11, 2007 by BLAST FROM THE PAST

[Optimus Prime]

CET according to Metcheck is now 7.7c, drop of 0.6c. Another 0.6c drop tomorrow.

GFS run predicts the average temperature from tonight to the 15th will be 1.5c. The CET by the 15th should be around 6.1c.

[eddie]

We have never got a final CET figure below 4.7C from a rolling mean >= 8C by the 10th. I would suggest that a final CET much below average is looking unlikely at this point.

[West is Best]

We have never got a final CET figure below 4.7C from a rolling mean >= 8C by the 10th. I would suggest that a final CET much below average is looking unlikely at this point.

Before SF leaps in to your defence, can I just point something out Eddie? The current projections look like producing a CET at 4.5C by close of play on 20th, give or take (might well be lower than that). It would be worth your while popping that into the chart you have there and you'll see that there's simply nothing like it, and therefore nothing with which to compare. There will never have been such a dramatic turnaround between the first 10 days and the second 10 days. So then re-run it from 4.5C after 20th and see where it may land us. You'll see the point I'm making?

I've knocked it up using dots here:

Edited December 11, 2007 by La Nina

[eddie]

Before SF leaps in to your defence, can I just point something out Eddie? The current projections look like producing a CET at 4.5C by close of play on 20th, give or take (might well be lower than that). It would be worth your while popping that into the chart you have there and you'll see that there's simply nothing like it, and therefore nothing with which to compare. There will never have been such a dramatic turnaround between the first 10 days and the second 10 days. So then re-run it from 4.5C after 20th and see where it may land us. You'll see the point I'm making?

I've knocked it up using dots here:

Yes, I understand what you are saying, but even if we get to 4.5C by the 20th that doesn't guarentee a sub 4.7c finish.

The period from the 21st to the 31st would also have to be below 5.1C. The entire period from the 11th to the 31st would have to be below 3.1C. /Edit : got that bit about 1993 wrong.

I'm not saying it won't happen, I just think it unlikely.

Edited December 11, 2007 by eddie

[Stratos Ferric]

Before SF leaps in to your defence, can I just point something out Eddie? The current projections look like producing a CET at 4.5C by close of play on 20th, give or take (might well be lower than that). It would be worth your while popping that into the chart you have there and you'll see that there's simply nothing like it, and therefore nothing with which to compare. There will never have been such a dramatic turnaround between the first 10 days and the second 10 days. So then re-run it from 4.5C after 20th and see where it may land us. You'll see the point I'm making?

I've knocked it up using dots here:

Ah but WiB, we've had this discussion more than once already this autumn. The argument hinges on continuing cold. Yes, we're due a big drop to the 20th, say, but in the christmas pudding cold that persists more than 10 days is rare indeed. The suggestion is that we would have spent most of this month's allowance by the 20th and continuing cold would be very unlikely. I grant you it's not impossible, but equally, it's also not impossible that the pattern will break before then, and that the surface won't be quite so cold as GFE has been suggesting.

It's a fair point to say extrapolate from the 20th, but it presupposes we get there on 4.5C. I must admit that on the basis of charts I've been looking at that seems a tad low, surprising though this must be to everyone given your recent record of impartial assessment.

We have never got a final CET figure below 4.7C from a rolling mean >= 8C by the 10th. I would suggest that a final CET much below average is looking unlikely at this point.

Eddie, good chart. How's about reverse engineering as well. Of the months that did finish 4.7 or below, where were they on the 10th. The fact that it might not have happened before doesn't rule it out absolutely of course, but it would, in the even larger teapot, make any such occurrence this time all the more notable.

Edited December 11, 2007 by Stratos Ferric

[VillagePlank]

... but in the christmas pudding cold that persists more than 10 days is rare indeed ...

Was it not always thus? Perhaps the magnitude of, say, a ten day spell was more significant (it was colder), therefore affecting the CET that much more, but, for instance, what is the frequency of >10 day spell recording <CET average for the same period over, say, a century, in winter time.

I haven't looked at the data (so perhaps I should), but I'd hazard a wild guess at, say, once every five years, perhaps.

[Optimus Prime]

According to Hadley last night made a -0.8c difference. Was 5.7c yesterday now 4.9c but it's still exceptionally above average at +2.7c. Should be down to 4.4c by tomorrow.

Maxima has yet to update but I suspect after a cold (ish) day today it should be down from 10.5c on the 10th to 9.9c and another 0.5c drop tomorrow.

Hadley looks to be around the 7.4c mark at present. Running below Metcheck and netweather.

[Weather-history]

. Of the months that did finish 4.7 or below, where were they on the 10th. The fact that it might not have happened before doesn't rule it out absolutely of course, but it would, in the even larger teapot, make any such occurrence this time all the more notable.

Well you only have to look at November 2005, that was comfortably well above average by halfway and by month's end it was below average.

December 1992 was comfortably above average by halfway mark but ended up comfortably below average by month's end.

If you look at Decembers 1979 and 2000 at the halfway marks

1979 was 8.7 by the end it was 5.8

2000 was 9.1 by the end it was 5.8

This December is going to be below those halfway figures comfortably by the 15th.

Edited December 11, 2007 by Mr_Data

[eddie]

Eddie, good chart. How's about reverse engineering as well. Of the months that did finish 4.7 or below, where were they on the 10th. The fact that it might not have happened before doesn't rule it out absolutely of course, but it would, in the even larger teapot, make any such occurrence this time all the more notable.

There are 133 Decembers in since 1772 that finished below 4.7C and I can't be bothered to add them all to a chart .

To be fair to La Nina (I didn't know this was WiB?) the period of the the 1st-10th 1794 was a fraction below 8C and that ended up at 3.7C

1794/95 really was a freak winter though. Januay 1795 was -3.1C and Feb was 0.8C. I will declare AGW is over if we get a repeat of that.

[West is Best]

Yes, I understand what you are saying, but even if we get to 4.5C by the 20th that doesn't guarentee a sub 4.7c finish.

No I agree, but I think you're missing my point as is SF. It's that according to your graphs this will already be completely unprecedented by the 20th and by an enormous margin (nearly 2C) - it's going to be massively off your scale. So I'm not talking about whether or not 21st to 31st is or isn't cold, I'm merely pointing out that over the next 10 days this month will have completely torn up all arguments relying on precedence . They are little pieces blown out of the window.

1979 was 8.7 by the end it was 5.8

2000 was 9.1 by the end it was 5.8

This December is going to be below those halfway figures comfortably by the 15th.

Yes, which rather goes to show how it entirely depends on what marker you use.

We're going to be something around 4.5C by 20th (even give or take 0.5C doesn't alter the extent of this). I'd be really really interested to know what the mean outcome is from that point to the end, plus the median figure and finally the range.

Edited December 11, 2007 by La Nina

[Roger J Smith]

I'm expecting the CET to fall to 4.7 by the 20th, then rally to 5.7 by the 28th, then fall off to 5.5 by the 31st.

If it doesn't, I may join a monastery, especially if they have good food.

[eddie]

No I agree, but I think you're missing my point as is SF. It's that according to your graphs this will already be completely unprecedented by the 20th and by an enormous margin (nearly 2C) - it's going to be massively off your scale. So I'm not talking about whether or not 21st to 31st is or isn't cold, I'm merely pointing out that over the next 10 days this month will have completely torn up all arguments relying on precedence . They are little pieces blown out of the window.

Yes, which rather goes to show how it entirely depends on what marker you use.

We're going to be something around 4.5C by 20th (even give or take 0.5C doesn't alter the extent of this). I'd be really really interested to know what the mean outcome is from that point to the end, plus the median figure and finally the range.

Well as always, time will tell. I personally don't think it will be anywhere near cold enough to get down to 4.5C by the 20th. I would be suprised if it goes below 5.5C.

Incidentally, for a month that falls between 4C and 5C by the 20th:

Average 4.2C, Min 2.2C, Max 5.7C Median 4.2C

[Stratos Ferric]

Was it not always thus? Perhaps the magnitude of, say, a ten day spell was more significant (it was colder), therefore affecting the CET that much more, but, for instance, what is the frequency of >10 day spell recording <CET average for the same period over, say, a century, in winter time.

I haven't looked at the data (so perhaps I should), but I'd hazard a wild guess at, say, once every five years, perhaps.

It's coming - soon...

...

We're going to be something around 4.5C by 20th (even give or take 0.5C doesn't alter the extent of this). I'd be really really interested to know what the mean outcome is from that point to the end, plus the median figure and finally the range.

That's still flawed WiB, sorry. It's easier to get ten days of cold (i.e what would be required to correct us to the level you project - though I suspect that is significantly too cold by the way) than twenty. It's like me running a 10k road race with a PB of 37 minutes, and trying to catch up with the leader at around 6k. He will be capable of running sub 30 so even if I did catch him I'd by then be incapable of even a slow walk thereafter. Any forward extrapolation really would need to be based on similar circumstances. We had this discussion in October and November and the case was proven both times.

Well as always, time will tell. I personally don't think it will be anywhere near cold enough to get down to 4.5C by the 20th. I would be suprised if it goes below 5.5C.

Incidentally, for a month that falls between 4C and 5C by the 20th:

Average 4.2C, Min 2.2C, Max 5.7C Median 4.2C

That would be my instinct as well, though I haven't checked today's models closely. None of the runs I've seen over the past couple of days have got as low as 4.5 without some wishful thinking.

[Stu_London]

It's coming - soon...

That's still flawed WiB, sorry. It's easier to get ten days of cold (i.e what would be required to correct us to the level you project - though I suspect that is significantly too cold by the way) than twenty. It's like me running a 10k road race with a PB of 37 minutes, and trying to catch up with the leader at around 6k. He will be capable of running sub 30 so even if I did catch him I'd by then be incapable of even a slow walk thereafter. Any forward extrapolation really would need to be based on similar circumstances. We had this discussion in October and November and the case was proven both times.

So you are saying mild must follow cold and that the weather has a memory?

[Stratos Ferric]

No I agree, but I think you're missing my point as is SF. It's that according to your graphs this will already be completely unprecedented by the 20th and by an enormous margin (nearly 2C) - it's going to be massively off your scale. So I'm not talking about whether or not 21st to 31st is or isn't cold, I'm merely pointing out that over the next 10 days this month will have completely torn up all arguments relying on precedence . They are little pieces blown out of the window.

...

Quite agree that the correction against the population would be outstanding, though clearly not at all "off the scale". Let's wait for it to happen first though, and then see whether the drop is sustained to the month end.

Your hyperbole around cold isn't abating is it?

[Gavin P]

Richard

As you know I'm a cycle supporter and we have entered perturbation cycle on Feb 2007 [La Nina domination from El Nino domination]...funny the El Nino 'collapsed' in Feb and folk were surprised...I wasn't as I followed Theodore Landscheidts predictions and were very good. I say were as he is dead now since 2003 but he predicted this and also sun cycle 23 being quieter than expected and 24 being much quieter and this seems a very good call.

Just to stay on topic the mild period over Christmas IMO will keep us at around mid 5s possibly 6./

BFTP

Very interesting Blast. Have you got any more information on Theodore Landscheidts predictions ?

Edited December 11, 2007 by Gavin P

[JohnAcc]

The ECM and GFS are both now picking up on the trend for the high to retrogress westwards over the UK in the later time frames which will result in us having continued seasonal ground temps for a while longer.

I have updated yesterdays projections with this mornings 06z run and it will be interesting to see where we end up and how close the GFS is. I seem to recall SF saying last month that the GFS pretty much nailed temps from quite an early period.

This mornings output would return us a CET bang on the 71-00 average

Rgds, John

[Joneseye]

I am surprised at the lack of posts on this thread today:

CET: (Dec 1-11): 7.7°C (+2.2 degC)

E&W Rain: (Dec 1-11): 49.7mm (138 per cent)

E&W Sun: (Dec 1-11): 22.1hr (131 per cent)

from http://www.climate-uk.com/

EDIT - just seen your post John... so a drop of 0.4C yesterday without looking at the rounding that may have taken place.

Edited December 12, 2007 by Joneseye

[JohnAcc]

Could be a fall of 0.4 or even 0.5 after today.

Hi Joneseye,

Yes Kevin called this one earlier yesterday morning. A 0.4 drop yesterday and from what I can see a further 0.4 drop per day for the next 4 or 5 days (depending on cloud cover). I fear my 6.1 and your 5.9 may, just may be a tad on the "high" side.

Rgds, John